In the paper industry, it is well-known that large diameter rolls of paper are processed to provide the numerous types, styles, formats, etc. of paper media that are used in the business world. From the paper manufacturing industry to the retail supplier of the paper media, there are instances wherein defects occur in the product so as to cause wasted material and/or operations or require replacement of defective goods.
In the business forms printing industry, these large diameter rolls of paper are processed to provide various types of business forms for customers to be used in their businesses. For example, one area of application in such business forms printing industry involves the use of a rotary web fed printing press and a rotary web fed collator in a process line.
In a press operation, a roll of paper is placed in position on a cradle at one end of the process line and the paper is unwound from the roll for use in one or more operations, such as printing, coating, imaging or other like operations on the paper. The paper is then rewound at the other end of the process line in either a face in or a face out manner depending upon the process and procedure employed or required in the operation.
The press operator observes the overall operation and when any defective material is found, the press is stopped, the problem is corrected, the press is restarted and the operator then manually inserts a flag in the form of a small, approximately 1".times.6" strip of paper at the edge of the paper being rewound to indicate that good material is being rewound.
One of the problems encountered in working with paper media is that of defective material, such as holes in the paper, uneven splices, tears, etc. which defects require detection and correction so as to insure good products for the customers. Depending upon the extent of the defect, it may be possible to correct or to repair the defect, or if necessary, to delete the defective material from the roll of paper.
When a defect is seen by the operator at a particular position in the web of paper, the operator stops the line, corrects the problem, restarts the press and allows material to run until the defective portion or area of the paper passes and the point of good material is observed. At this point the operator flags the roll of paper to indicate that good material is running. Since a number of defects or defective portions may be observed in a roll of paper, the roll may include a number of flags sticking out from the edge in the rewound roll. It is to be noted that the manual method of flagging the paper invites some danger to the operator and also causes excessive waste of material if the operator allows excess paper to pass before a flag is inserted in the edge of the roll.
When the flagging is completed and the paper is rewound, the rewound roll is moved to a collating line where further processing and operations, such as slitting, unit forming, etc. are performed. The roll of paper may be positioned in reverse manner or the roll may be reversed to enable flow of the paper along the collating line in the reverse manner. In this respect, the flags which were placed along the paper and which are visible by the operator by reason of extending or sticking out from the edge of the roll of paper readily indicate the position of good material and that the defective material is approaching. The defective material then can be corrected or can be deleted from the roll of paper. This procedure, of course, necessitates stopping the collator machine for each and every defect in the paper material. The defect may be a hole in the paper, a number of holes at a certain location, a tear along the web of paper, defective print quality, or an uneven web splice, to name some of the common defects or problems.
Representative documentation in the field of detecting codes on continuously moving webs includes U.S. Pat. No. 4,673,803, issued to L. Zerle et al. on June 16, 1987 which discloses identification marks in the form of code fields, preceded by a starter label, arranged on a material band and recognized by a reader head.